The present invention generally relates to a low drop-out voltage regulator and, more particularly, to a voltage regulator that tracks and compensates load current, and a corresponding method for tracking and compensating load current.
High performance power supplies use low drop-out voltage regulators (LDO) as power converters for their improved efficiency and reduced noise. For these reasons, LDOs also are widely used in various devices like mobile phones, electronic instruments, portable computers, etc.
A typical LDO includes an error amplifier, an output stage, and a sampling and feedback circuit. The sampling and feedback circuit samples an output voltage provided by the output stage, and feeds back to the error amplifier, such that a voltage feedback loop is formed to ensure a stable output of the LDO.
In operation, the output current of the LDO varies with connected loads. Specifically, in some of the applications, variations in load are remarkable such that the output current fluctuates beyond the range of stable operation. Further, mutual interference exists between the load and the intrinsic control loop of the LDO, which effects the frequency response and output stability of the LDO.
The present invention provides a low drop-out voltage regulator with improved output stability along with actual load current variations. The present invention also provides a corresponding method for a low drop-out voltage regulator to track and compensate load current.